• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.21-29
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• 2014

This paper deals with the bonding characteristic of grouted joint connections of monopile support structures for offshore wind power facilities. For the integration of pile connection of wind power supporting structure, fiber reinforced high performance cementeous grout was developed and the ultimate compressive strength of it is 125MPa and the direct tensile strength is 7.5 MPa at 7 days. To assess the bond strength of grout filled in pile connection, small scaled direct bond tests under axially loaded was performed and analyzed according the existing guidelines. The fiber volume fraction (0%, 0.5% and 0.9%), aspect ratio of fiber (60 and 80) and the ratio of height to spacing of shear key (0.013 and 0.056) were adopted as the experimental variables. From the test results, the maximum bond strength among the all specimens was 30.8MPa and the bond strength of grouted connection was affected by the ratio of height to spacing of shear key than the fiber volume fraction.

• Bulletin of the Society of Naval Architects of Korea
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• v.18 no.1
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• pp.1-8
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• 1981

To contribute to the preventive measures against local vibrations of ship's deck panels, some investigations into the prediction method of the natural frequency of the vibration of stiffened plates were done. Firstly, an analytical method based on the orthotropic plate analogy and the Rayleigh method using eigenfunctions of the Euler beam was shown, and numerical results of a regularly stiffened plate were compared with experimental results. And then, the method was extended to stiffened plates having one or two irregular stiffeners to obtain an approximate formula showing the relation between the change of the natural frequency and the size of the irregular stiffeners. The latter case was investigated for the purpose of providing a convenient design manual applicable to cure of local resonant vibrations of ships' deck panels by additional reinforcement of one or two stiffeners. In the analytical development the boundary was assumed to be rigidly supported and elastically restrained against rotation. In the experiment, however, only an extreme case i.e. simply supported boundary was investigated. The results of the investigation show that there is a fairly good conformity between the analytical results and the experimental ones in the first case, and that the approximate formula for the second case is confirmed also to be reliable for the design purpose. Considering that actual boundary conditions of deck panels in ship structures lie mostly somewhere between the simple support and the fixed, the authors discussed problems of the joint efficiency at the boundary of deck panels from the viewpoint of the practical application of the formulae.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.274-280
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• 2014

The spermatozoa of Platichthys stellatus is relatively simple cells composed of a spherical head, a short midpiece, and a tail, as in most Pleuronectiformes. The ultrastructure is characterized by the following features: a round nucleus with a deep nuclear fossa, the centriolar complex located at a right angle to each other, a short midpiece, a tail with paired lateral ribbon and no acrosome. However there are some minor morphological differences, including the appearance and number of the mitochondria, the shape and size of the nuclear fossa and the structure of the basal body. Especially the basal body structure consisting of a basal foot, a rootlet and nine alar sheets structures varies considerably in different species. It can be used as indicator of relationships in Pleuronectiformes because minute morphological differences might have functional and evolutionary significance. In conclusion, the spermatozoa of P. stellatus show a certain structural homogeneity and provide support for the concept that ultrastructural features of spermatozoa can be useful in taxonomic studies of Pleuronectiformes.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.1
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• pp.55-61
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• 2008

A real-time three-dimensional vision is a passive system, which would support various applications including collision avoidance, home networks. It is a good alternative of active systems, which are subject to interference in noisy environments. In this paper, we designed a SAD correlator with respect to resource usage for a real-time three-dimensional vision system. Regular structures, linear data flow and abundant parallelism make the correlation algorithm a good candidate for a reconfigurable hardware. We implemented two versions of SAD correlator in HDL and synthesized them to determine resource requirements and performance. From the experiment we show that the SAD correlator fits into reconfigurable hardware in marginal cost and can handle about 30 frames/sec with $640{\times}480$ images.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3A
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• pp.139-148
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• 2012

Circular concrete-filled tubes (CFTs) are composite members, which consists of a steel tube and concrete infill. CFTs have been used as building columns and bridge piers due to several advantages such as their strength-to-size efficiency and facilitation of rapid construction. Extensive experimental studies about CFT have been conducted for past decades. However experimental results alone are not sufficient to support the engineering of these components. Complementary advanced numerical models are needed to simulate the behavior of CFT to extend the experimental research and develop predictive tools required for design and evaluation of structural systems. In this study, a finite element modeling technique for CFT was developed. The confinement effects, and behavior of CFT subjected various types of loading predicted by the proposed finite element model for CFT were verified by comparing with test results.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.61.1-61.1
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• 2014

GSH 006-15+7 is a Milky Way supershell discovered by Moss et al. (2012). This supershell shows large shell-like structures in H I velocity maps. We have analyzed FUV emission for the supershell regions based on the FIMS and GALEX observations. Bright FUV flux at the boundaries of the supershell is mostly originated from dust scattering of FUV photons by dust clouds which was also observed at the boundaries of the supershell. We could find the distance to the supershell can be closer more than 30% compared with the distance of 1500 pc suggested by Moss et al. (2012) from the dust scattering simulation. And we also found the albedo and the phase function asymmetry factor of interstellar grains were 0.30 and 0.40, respectively. The confidence range for the albedo covers the theoretical value of 0.40, but g-factor is rather smaller than the theoretical value of 0.65. The small g-factor might mean the environment of turbulent ISM of the supershell. Meanwhile, the excess of C IV and X-ray emissions in the inside of the supershell can support the existence of hot gas and cooling in the supershell. And the C IV and X-ray emissions are monotonically decrease as away from the center of the SNR. This indicates the size of the hot bubble has considerably shrunk. We applied a simple simulation model to the PDR candidate region of the lower part of the supershell and obtained a H2 column density N(H2) = 1017.0-18.0 cm-2 and total hydrogen density nH ${\geq}$ 10 cm-3. This result shows the PDR candidate region represents a transition region from the warm phase to the cool phase in the PDR.

• Journal of Hydrogen and New Energy
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• v.22 no.5
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• pp.599-608
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• 2011

The Ni-Al anodes of the molten carbonate fuel cell (MCFC) with three different structures were successfully fabricated in order to reduce the thickness of the anode down to 0.3 mm; one was the non-supported anode made by a conventional tape casting method, and others were the supported anodes made by lamination or direct casting on the nickel screen. It was seen from the physical analyses and cell operation that the supported thin anodes made by direct casting showed good mechanical strength and cell performance because of a good contact between the anode materials and the support. The single cell using the above anode showed the cell voltage of 0.858 V at the current density of 150$mA/cm^2$ with the nitrogen cross-over of only 0.6% at the operation time of 1,000 h, which was similar to the performance of the conventional thick (0.7 mm) anode. The ability to utilize a thin configuration of anode should cut down the amount of nickel alloy and consequently reduce its manufacturing cost.

• Journal of Families and Better Life
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• v.29 no.4
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• pp.125-145
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• 2011

The purposes of this study were to examine low-income households' financial statuses and the socio-economic characteristics of single-person and non-single person households according to the financial indexes used for evaluating financial security and growth status developed based on financial ratios. Using 2009 KLIPS(Korean Labor & Income Panel Survey) data collected by the Korean Labor Institute, the satisfaction levels from the indexes were analyzed and compared between the two household types. The results showed that 46.0% of single-person households were not satisfactory in terms of all financial growth indexes but were partially satisfactory in terms of all financial security indexes. These householders tended to be females and in the their 70s, who lived in Seoul or in a suburb of Seoul, Korea. They reported problems with a lack of financial growth possibilities. 47.0% of non-single person households were not satisfactory in terms of all financial growth indexes but were partially satisfactory in terms of all financial security indexes. These householders tended to be males in their 60s and 70s with no job who were living in Seoul or in a suburb of Seoul, Korea. They reported having low level of liquidity and high level of debt redemption. 42.6% of single-person households were not satisfactory in terms of both financial security and growth indexes partially. These householders tended to be females in their 20s or 70s who were living in rural areas. They reported problems related to an adverse balance between household income and expenditures and a large scale of debt. 43.1% of non-single households were not satisfactory in terms of both financial security and growth indexes partially. These householders tended to be males in their 60s or 70s and homeowners. They reported problem related to an adverse balance of household income and expenditures and high a level of housing expenditures and liquidity. The research findings have implication for policy makers considering financial support programs and welfare programs for low-income householders, considering the recent changes in households structures.

• Spatial Information Research
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• v.18 no.2
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• pp.1-12
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• 2010

At present, monitoring programmes for green network have been mainly based on field sampling, which relies on attributes of an area at one point in time, reflecting an emphasis on the small number of in-situ data. One of the major disadvantages of traditional field monitoring is that it is costly, laborious and time consuming due to the large number of samples required. The aim of this research was to evaluate green network based on pixel of Landsat TM satellite image. An empirical study for a case study site was conducted to demonstrate how a standard remote sensing technology can be used to assist in monitoring the green network based on pixel. The pixel-based analysis made it possible to identify area-wide patterns of green network subject to many different type of artificial structures, which cannot be acquired by traditional field sampling. It was demonstrated that the degradation trends of green network could be used effectively as an indicator to restrict further development of the sites since the quantitative data generated from remote sensing can present area-wide visual evidences by permanent record. It is anticipated that this research output could be used as a valuable reference to support more scientific and objective decision-making in monitoring green network.

• Wind and Structures
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• v.2 no.3
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• pp.133-150
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• 1999

Significant costs to the public and private sectors due to recent extreme wind events have motivated the need for systematic post-hurricane damage data collection and analysis. Current post disaster data are collected by many different interested groups such as government agencies, voluntary disaster relief agencies, representatives of media companies, academicians and companies in the private sector. Each group has an interest in a particular type of data. However, members of each group collect data using different techniques. This disparity in data is not conducive to quantifying damage data and, therefore, inhibits the statistical and spatial description of damage and comparisons of damage among different extreme wind events. The data collection does not allow comparisons of data or results of analyses within a group and also prohibits comparison of damage data and information among different groups. Typically, analyses of data from a given event lead to different conclusion depending upon the definition of damage used by individual investigators and the type of data collected making it difficult for members of groups to compare the results of their analyses with a common language and basis. A formal method of data collection and analysis-within any single group-would allow comparisons to be made among different individuals, hazardous events and eventually among different groups, thus facilitating the management and reduction of damage due to future disaster. This research introduces a definition of damage to single family dwellings, and a common method of data collection and analysis suited for groups interested in regional characterization of damage. The current state-of-data is presented and a method for data collection is recommended based on these existing data collection methods. A fixed-scale damage index is proposed to consider the damage to a dwelling's feature. Finally, the damage index is applied to three dwellings damaged by Hurricane Iniki (1992). The damage index reflects the reduced functionality of a structure as a single family detached dwelling and provides a means to evaluate regional damage due to a single event or to compare damage due to events of different severity. Evaluation of the damage index and the data available support recommendation for future data collection efforts.